An optical semiconductor apparatus, which is used widely in a display apparatus, a device for display, or the like, is equipped with a light emitting diode (LED) chip as a light emitting device. In the apparatus, the LED chip is mounted on a light emitting side of a lead frame, is electrically connected with the lead frame by wire bonding, and in addition, is sealed with a resin which protects the light emitting device and also has a function as a lens.
As a sealing material used at the time of sealing the light emitting device such as the LED chip, an epoxy resin is used in many cases for the reasons of its easiness of processability, being transparent, and the like. In the case where a bisphenol A epoxy resin, which is a typical epoxy resin, is used for sealing LED having a short wavelength such as blue, ultraviolet, or white which is a combined color of them, there has been a problem that the bisphenol A epoxy resin absorbs light and turns yellow to be deteriorated, because, in spite of having heat resistance, the bisphenol A epoxy resin contains an aromatic component. In order to solve the problem, there is proposed an LED sealing agent using a bisphenol A epoxy resin in which an aromatic ring is hydrogenated (refer to Patent Document 1). The hydrogenated bisphenol A epoxy resin is not deteriorated by light, but does not have enough heat resistance to withstand the heat generated at the time of light emission.
On the other hand, an adamantane has a structure in which 4 cyclohexane rings are condensed to form a cage skeleton, and is a highly symmetric and stable compound. Further, a derivative thereof has optical characteristics, heat resistance, and the like, and hence, attempts have been made to use the derivative for an optical disk substrate, an optical fiber, a lens, or the like (refer to Patent Document 2 and Patent Document 3). Further, an attempt has been made to use adamantane esters as a resin raw material for photoresist by utilizing their acid sensitivity, dry etching resistance, ultraviolet transmission property, and the like (refer to Patent Document 4). In addition, a proposal has been made that an epoxy compound derived from adamantane diols is used as a sealing agent for a light emitting diode, and it has been reported that the epoxy resin has heat resistance and light resistance (refer to Patent Document 5). However, the yield of a cyclic ether compound, which is obtained from a reaction of the adamantane diols with a cyclic ether group-containing compound typified by epichlorohydrin, is low resulting from the low reactivity of the adamantane diols. In order to obtain the cyclic ether compound at high yield, it is necessary to go through a complex reaction pathway, and hence, the proposal is not industrially useful.
Patent Document 1: JP 2003-082062 A    Patent Document 2: JP 06-305044 A    Patent Document 3: JP 09-302077 A    Patent Document 4: JP 04-39665 A    Patent Document 5: JP 2005-146253 A